No one was in the corrugated-steel building at the time of the fire. The cause of the blaze has not been determined, Shelton Deputy Chief Tim Hongo said.

The building, which is used to store construction and demolition debris, is located near the "Amazing Green Machine," a $15 million facility that processes and bundles single-stream recyclables.

The call was first reported as a brush fire, but when firefighters arrived, they discovered the building was on fire.

After getting the blaze under control, firefighters thoroughly wet down the building and popped holes in the back to ventilate it. Firefighters expected to be on scene for several more hours as the fire burned itself out, officials said.

Hongo said two firefighters were overcome by heat and another sustained an unknown minor injury.

Crews from Derby and Ansonia were among the departments that responded with mutual aid.